hi, back before the internet, I would hear that is best to refill on gasoline at a quarter tank, because when the tank is low it's more likely for fuel to burn, which is not so great for the car and fuel filters.

is this still the case for diesel? or for a W123?

I never had a reason to question it, and just refilled at 1/4 for years, but the reason I'm curious now is because I am traveling 30min to buy B99 biodiesel every 2 wks, but could maybe stretch it to 3 weeks if there's no issue with running lower on the tank.

I saw the specs for my fuel tank are about 21 gallons, and I think about 7 gallons for reserve? when I am at a quarter tank and refill it gets fill at about 13.5 gallons.

thanks!